U.S. Pat. No. 3,422,008 to McLain shows a method of manufacturing blood dialyzers by winding hollow fibers onto a mandrel. In the McLain patent, the fibers are wound on a rather long mandrel and are provided with tube sheets of epoxy which secure the fibers together at intervals along the mandrel. The tube sheets are subsequently cut in half, transversely to the mandrel, to form individual cartridges in conjunction with the mandrel and fibers.
In the bulk stage, the hollow fibers used in the construction of these blood dialyzers are partially filled, and their walls are saturated, with an organic oil as a consequence of manufacture. This oil reduces the adhesion of the hollow fibers to the tube sheets and is prone to result in leakage. The oil must also be removed from the interior of the fibers before the dialyzer is used.
It is thus desirable to wash the fibers after winding and before the permanent tube sheets are applied as shown in McLain. In the absence of the tube sheets, however, the fibers have no structural integrity and cannot be easily handled.